Dynamo-electric machine.



E. J. ANDREWSQ DYNAMO ELBUTRXG MACHINE.

APPLIOATION FILED JULY 5, 1907.

1,123,161, Patented De0.29,1914.

4 SHEETS-SHEET l.

E. J. ANDREWS. DYNAMO ELEGTRIG MACHINE.

APPLICATION FILED JULY 5, 1907. 1 ,1 23,1 6 1, Patented Dec. 29, 1914.

4 SHEETSSEIEET2.

HUN HHHHIHIIEHHIIHHHH I im W -E. J. ANDREWS.

DYNAMO ELECTRIC M AGHINE. APPLICATION FILED JULY 5, 1907.

1,123,161. Y r Patented De'c.29,1914.

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EEHEEEEEBEBEEJEEEHEH@ EE@E EEHH Patented D60. 29, 1914.

STATES PATENT orinon." j

framers. ANDREWS, or

CHICAGO, ILLINOIS, ASSIGNQR OF ONE-FOURTH TO GEORGE I4. I CHINDAHL, OF CHICAGO, ILLINOIS.

nYNAMo-nLEc'riaic MACHINE- To all whom it may concern Be it known that I, ERNEST J. ANDRnws, ii citizen of the United States, residing at Chicago, in thecounty' of Cook and State of Illinois, have invented certain new and useful'Ii'nprovements in Dynamo-Electric Ma chines, of which the following is .a specification.

One of the objects of my invention is the provision of improved means for regulating the power capacity of dynamo-electric machines.

My invention relates to the regulation of the speed of dynamo-electric motors b'y varying the inductive length of the armature conductor in series, and thereby coincidently varying the counter electroniotive force of the motor, and by the same means regulating the electromotive-force of so-called dynamoelectric generators, or current-producers.

The invention also relates to other improvements in dynamo-electric machines hereinafter set forth.

- In the accompanying drawings, Figure 1 is a diagrammatic representation of an arinature'winding embodying some of the features of my invention. Fig. 2 is a side view of a mechanism for-changing and varying the current paths or the electric circuits through the armature. 3 is an end eleivation' of the part hereinfater termed the regulator cylinder. Fig. 4c is-a detail view of one of the movable contact members,

.partly in section. Fig. 5 is a fragmentary, 35

. struction of the regulator cylinder.

enlarged detail view, illustrating the con- Fig. 6 is a fragmentary cross-sectional view of the same. Fig. 7 shows a single armature coil with its various turns. Fig. 8 is a flat development of the periphery of the regulator cylinder Fig. 9 is a flat developmentofthe inner surface of said cylinder Fig. 10 15 a flatdevelopment of the inner surface of the movable contact ring. Fig. 11 is a schematic development of connections of the various coils, or sections, of the armature to "produce 'ma-ximum electro-motive-force, or counter-electro-motive-force, as the case may be, which I will call simplex winding. Fig. 112 .is a similar though modified scheme,

showing certain of the coils in parallel rela- Specification of Letters Patent.

sub-paralleling of certain of the coils. Fig;

15 is an arrangement of coils by means of which three uniform current paths, or circuits are provided around each side of the armature. This arrangement I have called triplex winding. Fig. 16 is a modification I of the arrangement similar to. that shown in Fig. 15, but showing sub-paralleling of the coils at certain selected parts of the armature. Fig. l7-is a'scheme of connections by which four uniform current paths or circuits are provided around each side of the armature. This arrangement I call quadruplex winding. v

In all of the views the same reference characters refer always to the same parts.

It is well known that in dynamo-electric machines in which the extent and density of the magnetic field of force is constant, the electron otive force mayfbe varied by in creasing the speed of the armature or by increasing the active length of the inducing conductor, or both. A given turn of wire on an armature will generate adefinite electroniotive force. If all of the turns or coils be joined in series the electromotive force will equal the sum of that o'fthe several coils.

If they be connected in parallel the. electromotive force willequal that generated by a single coil. p

My invention contemplates obtaining a Patented Dec. 29, 1914. I Application filed July 5, 1907. Serial No. 382,156. i

ready adjustmentof the speed ofa motor or g the electromoti've force of a generatorfby varying the number of armaturetu'rns or coils in series, other factors remaining substantially constant, without impairing the inherent qualities of such a machine to operate at constant speed, under varying con ditions of load, or constant electromotive force after each change has been eiiected.

.Figure 1 represents diagrammatically a wave-wound armature of a quadrupolar dynamo, opposite magnet field-poles being of the same polarity. C indicates the commutator, which isjsliown to contain 52 segments or bars numbered from 1 to 52, inclusive. The inductive sides of the coils of the armature winding represented by straight, approximately radial lines, are contained in slots or grooves made in the armature core, of which there are 26, indicated by the twenty-six letters of the alphabet, there being portions of four'difl'erent coils in each slot, z. 6., there are two coils per slot. Forthe sake of clearness, each coil is shown to consist of but one turn, and the number of coils and commutator sections are less than would usually obtain in practice.

' The inner portion of the diagram represents the commutator and its connecting leads. Theouter portion represents the rear end of the armature. The small circles located substantially. on the left of a median line, on the peripheral boundary of the diagram, represent the terminals of the coils which are connected in rarious ways by means of the regulator, or which may be in a few cases left open or disconnected. The

coil terminals which are in some cases left disconnected are 50', 5l'-, 52, 50", 51 and 5 2. In F g. 1 the last mentioned terminals are shown disconnected. The coil terminals represented by small circles are indicated in each case by a numeral corresponding with the reference number ofthe commutatorsection to which it is connected, with a prime exponent, from 1 to 24, inclusive, and with a second exponent from 25 to 52", inclusive. The prime numbers prime coil leads, and the double-prime num ,bers those connected to the double -pr1me leads. It will'be noticed that the coils leading to the terminals 50, 51 and 52' have each two such terminals, making 5% terminals for 52 coils. In the connections necessary to produce the varied results hereiir after explained, these three coils, in several instances, or some of them, are not included in the live circuit when such changes do not require the full number of coils contained in the armature. Although these reference numbers 50', 51 and 52 indicate normally open terminals, yet they are nowhere shown in Figs. 11 to -17, inclusive, forthe reason that whenever they are connected in any of the circuits they are always connected with the next adjacent terminal. Thus as 48 is always connected to 245" and 49 is always connected to 25", so is 50, when connected at all, always connected to 26", 51' to27", and 52 to 28";so that it is not necessary to so indicate in the various figures.

The field magnets of the diagram are indicated by M M, M" and M, the even numbers being of one polarity andthe' odd numbers of the other polarity.

The collecting brushes B and B are shown, forclearness, inside of the commutator, bearing on the commutator bars or segments. Each brush is sufficiently wide to span a little more than four commutator bars, for a purpose hereinafter more fully described.

The coil terminals are connected together by the wires (diagrammatically representing the controller connections). shown at the extreme periphery of the diagram, .on the left. Thus the coils are included in circuits in accordance with the schematic development of Fig. 11, when the coil terminals are connected as indicated in Fig. 1, resulting in that which I; term the simplex winding. This 'result is arrived at when the regulator contact ring indicated by Fig. 10 is placed in the position 1 of the regula= tor indicated by Figs. 8 and 9. The numbers with the dashes between indicate the coil terminalsswhich are connected. Th e numbers which liave dashes under them, r are underscored, represent coil terminals which are not included in the active circuit. The coils corresponding therewith, to wit, coils having terminals 50, 51' .and 52, are left open in scheme Fig. 11, and remain dead or inactive. r

It will be observed that beginning at com mutator section'l, thec'urrent will pass in two parallel paths through the armature,

both circuits finally terminating at the negative brush B One (path is from commutator segment 1 throu h slot A, in the direction indicated by. the arrow, to terminal 1, thence through the circuit-changer connection diagramamtically shown, to terminal 26" through slot E, in the direction shown by the arrow, this slot being near the neutral zone, then to commutator sect-ion26, then through slot- M to point 26 at the opposite side of the armature. through slot S to commutatocsection 2. This circuit maybe thus traced. touching commutator sections in regular sequence, and through the coils 1n the same order. until it terminates at'the brush B by the final wire leading from'terminal Q 3x the other half of the armature is from commutator section 1 through slot S, this slot being near the neutral Zone, to point 25- through slot M, this slot being near the neutral zone, to commutator section 25, through slot E to point25" 49 through slot Y back to commutator section 49', which is the next live section following. section 1 in that direction. From section 4.9 the circuit is completed, touching in regular sequence commutator section 48 to 42-, inclusive.

The first path which I have just outlined The parallel path or circuit through cci'ls which connect with. commutater, sectidns which I have arbitrarily In the arrangement of connectionsoutlined in'the schematic arrangement Fig. 11, and inrdiagr'am Fig. 1, it is shown that there are two sets ofg-c'oils in series, and that these sets are in parallel, or two-circuit relation,

from brush to brush,a connection which produces the highest electromotive force or the lowest speed, as a maximum number of coils are connected in series. I

When the disconnected ends or terminals of the coils are connected as indicated in Fig. 13, by means of my controller or circuit-changer to be hereinafter described, there will be four circuits through the ar mature, in which event thes'peed of'the ar- .mature of the motor will be doubled, for

then. there will'be'only half of the original number of coils '(shownin Fig..11) coniiected in series, and it will be necessary for the armature to revolve at double the number of-revolutions in order to produce the requisite counter electromotive force. The ac tive inductive armature conductorrlength being halved by this arrangement, the ve-- locity must becorrespondi'ngly increased;

the speed ratio is .two. By speed ratio I mean, whenever the term is used, the IiltlO- of the maximum to the minimum speeds. In this instance'the maximum speedis" two times theininimum speed. When the connections are made as indi-' cated in Fig. 15, there will be six circuits through the armature; thejspe'ed ratio is, in this illustration, three. v

IVhen'the coils are connected together as indicated in Fig. 17, there are eight circuits through the :armature from brush to brush, and the speed ratio is .four. I The schematic arrangements towhlch I have briefly referred show the connections to be made by means of my speed controller,

to double, triple or quadruple the speed of the revolving armature. t g

It is highly important that a definite and suitable numberof coils should be contained in the armature in orderto reach the highest efficiency and to attain the best operative i're'sul-ts under icertaln' 'glven ."conditions; 'There'ore 'a reliable formula [by 51 and 527 are not included in the circuit.

not by four,

'four, but not by eight.

means of which the desired" number of coils may be readily determined is of great value.

It is essential, -in order that each circuit shall return on -itself, after passingentirely around the armature, taking in each commutator segmentil'i the proper and regularlsequence or order, or every alternate commutator segment or every third or fourth segment, according to the type of circuit, as shown in Figs. 11', 13, 15 and 17, that the circuit shall contain an odd number of coils. The simplex winding (Fig. 11) should have an odd number of coils actually in use. The duplex winding (Fig .13) should have in use a number of coils divisible by two, but

vided, provides two halves, each an odd numb'er, so as to give two circuits passingentirely around the armature each an .odd number of coils. The triplex winding requires a winding having a number of coils divisible by three, but not by six. The qua'druplex winding should be divisible by or, a number-which, being di- Let n the speed ration, and a a Whole number, we should have in use with a machine of any ratio for the particular winding giving that speed ratio, .R-l-2nR.

coils. This formula, however, gives a different number for each schematic change, therefore -a compromise is necessary if the different schematic connections as herein illustrated are to beobtained.

With my method of connecting the various coils for different conditions of operation, or for various changes'of speed, there is greater tendency to spark at the commu tator when the connections are madefor high-speed operation, by paralleling thecircuits, because, owing to the parallel relation of the circuits andcommutator sections,

the total electro-motiveforce or difierenceof potential is broken'up by the fewer effective commutator breaks, and the potential drop between adjacentcommutator sections which are not in'circuitsparallel with each other, is correspondingly greater. Conditions,'it'or this reason, should favor the arrangement forproducing the highest speed.

Owing to the fact that certain'of the controllerconnections to produce the-.difierent graduations of speed, as illustrated in Figs.

11 to 17, inclusive,require a greater or less number of coils in the armature, in certain .arrangement'sfthere must necessarily be some coils that are noti'ncluded 1n the; BJOtlYG CIP- suit, as illustratedin F igs.-- 11,'12, and 3-13, while in the illustratiomFig. 17, for in stance, the'highestspeed arrangement, all of the 'coilsare included'initheective cir-: cuits. .7 1

. In order to fulfil all the conditions of the various. schematic illustrations,. -there must segments.

39 coils, and soon.

be someheaq coils with some. of the windings, and if-there are dead or inactive coils [in a particular schematic connection there -must be corresponding dead commutator In the maximum-speed connection '(Fig. '17), the. effective commutatorsegment surface is greater, owing to the paralleling of several adjacent commutator bars in their regular order. In other words,the

1 efi'ectiv'e commutator segments under these conditions are wider, consisting of four ad jacent bars; and a dead segment, in such a connection, would be an'additional surface for the brushes to bridge. Dead coils, therefore, in the maximum-speed connection would increase the, necessity for wider brushes, and cause a decrease in operative eflic1en'cyot the motor. Dead cells in the connections where the circuits are notpar- 2 alleled to such an extent would not operate -to require wider brushes; hence the con necticns whereby maximum speed is attained should control the number of coilsto be contained in the armature; and coilsin a5 excess of the number required for otherconnections may be left dead or idle in such: 1 iother connections.

Nowapplying the formula to the four ratio connection: R+2nR gives S4, 92, 100

For the three-ratio connection, we have 81, 87, i the four-ratio is to control,

the number of dead coils in the three ratio be there than live. In thetwo ratio there never ..5 would bemore than two dead coils. Butas this formula applied to any ratio will give many values tor the number of coils, it 1s possible to select from these values certam.

"that are best suited to the other connections. if for thefour ratio we take 1O0 co1ls it would give but one dead coil for the triplex connection (Fig;15). This should be considered when we want the highest eiiiciency attainable.

To give the best results for the three.-

ratio connectiomone coil less than the best number for the four ratio should equal the proper number for the three ratio; or jR-l-QnR-l shouldequal Rl+2n (R-1).

From this when R 4, 72 should equal 'n or three-fourths of some whole number.

But as wecannot have any fractions of a coil,

it must be multiplied by some whole number .fiWlliCll is a multiple 016%. The smallest nurn benis 3. Hence-we have the best number of coils for the four ratio: R+2 3nR But- 2 "3R==lR. in thiscase being equal to 1 2 3 Zl so that the number of coils should be R+nlR. This formula applies also to the three and to the two-ratio connections. These formulas, howeve1-, apply only to quadru 'aolar dynamo electric inachines, such as referred to in connect on with Fig. 1. ll'ith other types of machines the number of coils on the armature will be pro- 98, 99, andlso on.-; -1Ef in no case would portional to the number of field magnet poles. Hence for machines where other con- SldBtltICIiS than the highest elliciency enter as factors, the number of coils should be...

R+%R o. Nip,-

S0 for I have considered'tmly the full ratio changes 'in speed. I willnow discuss the fractional changes. The former I will call'theinajor changes and-the latter the minorchan'ges. A-CCIlSldel'ilblB portion of the valueoi my invention lies in the ability to make these minor changes of speed without materially decreasing the efliciency of the machine, andwhereby close regulation and slight variations as well as a large range are possible. I

The schematic connection indicated in Fig. 12 shows thegeneral method of obtaining the-minor changes. In this scheme some of the coils of the simplex scheme are shown placed in" parallel with-other coils-in the two parallel circuits extending from brush to brush, so that the total number of coils in series is correspondingly reduced. As the speed of the a-ianature is inversely proportional to the number of coils in series, it

may be thus gradually increased by the connections shown, and by further similar enlargements, until the duplex connection is reached. Similarly, circuit connections Fig. 14: show how the speed may be increased by further paralleling the coils of the armature from the duplexfto the triplex connections.

The circuit connections, Fig. 16, show a step between the triplex and the quadruplex or four ratio. r I

By referring to Fig. 1 it may be seen that the coils 29 and 30 which begin one of the shunts of circuit 12, he in'the same slot of the armature. If the shunt started with 2 and 29" it would start in different slots, the wires wouldliein magnetic fields of dilierent densities, and the electro-motiveforce generated in the two coils would be different. This would cause a local current to flow in and through the shunt itself, :which would cause extra Work and heat. Smilarly, coils corresponding with terminals 9 and 10'. are in the same slot, for the same reason. In order to obtain these results there must be two coils in each slot. But it is not suliicient. to start and to end theishunts in the same slots. lie in the same slots 0r cent throughout.

be otherwise adja- Referring to circuits Fig. 14Qwhich show The two branches mustshu'ntbeing closed before passing into difa. change between the duplex and the triplet: connections, if the shunt beginning with 29" and 30 were continued on and not-closed at 5' and 6' we should have 5" But method-of making the minor changes bethe duplex and the triplex connections. This is amultiple-shunt method, each ferent slots, and the complete change being produced by increasing the number of shunts.

In "order that the counter-'electro-motiveforce in the two'branches of the same shunt an equal number of coils. And in order that the counter electromotive force shall be the same in the various parallel circuits, the number of coils in series in all must be approximately equal; And thetwo halves of the 'difierent circuits must also have approximately the same number of coils. To

' obtain the latter the beginnings of the homologous shunts must be approximately one half of-the total number of coils in series apart.

\Vith reference to the form of the armature, we need consider next the arrangement of the coils in the slots of the armature.

mum speed connections must be favored.

- Fig. 17 .shows that the four-ratio winding is perfectly symmetrical. All of the others,

are unsymmetrical, and as these circuits are "simplex winding, Fig. 11, is the most unsymmetrical, Yet'the slow pitch, that is, the

numberfof slots from one side of a coil tothe other, is very important, because with brushes sufficiently broad to bridge the seg ments for the circuits of the maximum speed, the coils of the minimum speed connections will be short-circi 'ted, and if any of them are then in the acti i e magnetic field sparks and local currents will result. Considering first, armatures with several turns per coil, as is indicated in Fig. 7, and assuming that the wire shifted in each case is the last turn of the coil, in Fig. 1 it will be the wire indicated by the primed number. Thus wire 1', if connected to wire 29" by shifted backward by the regulator to 28" for the triplex system, to 27" for the duplex system, and to 26 for the simplex system or minimum speed position. In shifting, the pitch of the coil itself is not changed, as this depends only on the or ginal w ndmgof the coil. But the pitch from the last half of the coil which hes in slot G, to the-first half of the next which is in slot 0, is changed. By shifting 1' back to 26" the last half still lies in G, but the first half of the next coil now lies in M. The pitch of the coil itself was six, and remains so, but the pitch between the two coils is changed from 8 to 6. If the pitch between the coils 1 and 29" had been seven the pitch after shifting would have been five, and this would have .been too small because it would throw some 'of the coils of the simplex system into the active magnetic field and cause sparking.

' of the pitches would be too far from .the may be balanced, they must be composed of plies, however, to coils with several turns.

If there were but one or two turns per coil the case would be reversed. The pitch of the coils then should be as small as possible without being less than the average pitch.

We now come to a consideration of the means by which the coils are disconnected and reconnected in order to produce the system of circuits desired forany particular speed.

It is very motor, at least at certain times, may be desirable that the speed of the changed while the armature is rotating;

.to accomplish. this the regulator or circuitchanger should be placed upon the shaft of the armature so as to rotate with it. As a large number of the leads from the armature coils are necessarily connected to the circuitchanger, in order to reduce the length of these leads and to avoid unnecessary resistance of lead wires and other undesirable complications the circuit-changer should be placed as near the armature coils as possible. For this reason I prefer to place it at the rear end of the armature between the bearing and the armature core. It is also desirable to place the circuit-changer in the rear of the armature so that the bracket sustaining the front bearing of the shaft need not project so far from the main body of the motor. As the lengths of the commutator and of the circuit-changer are usually about the same, the machine with the circuit-changer in the rear is better balanced without impairing its stability and appearance.

T he success of the invention depends much upon reducing to a minimum the number of wire connections that arebroken and'made in making the necessary c anges.

-' electrically connected with and forms a ter- .The connections of Figs. 1 and 11" constitute a wave winding. In such a connection when the brush spans two commutator segments it shorts two coils in seriesag as for instance, in the simplex connections 26" and .2". It is a multiple winding when the brush shorts only one, or several in parallel. If it were a multiple or parallel winding and wire 1 were shifted backto 28" from 29", the only coil that would be affected would be 28". With the wave Winding, shifting wire 1'- carries with it coil-25". This at once reduces the number of connections that need to be brokenand remade, one half. -Hence the winding should be a wave winding.

The circuit-changing device or controller herein shown for conveniently and properly making the various connections outlinedin Figs. 11 to 17, inclusive, comprises a cylinder C rigidly mounted on and carried by the armature shaft F, and preferably at the rear end of the armature, between the core thereof and the armature shaft bearing. Said cylinder comprises a plurality of blocks G and bars C insulated from each other, but electrically connected byshort wires C into groups, shown in Fig. 9, some of said blocks and'bars extending the full length of the cylinder and'others but a part of said distance. .One barof each of said groups is minal'for each terminal of. those armature coils that are arranged to be opened and closed by the circuit changing device. The

terminals indicated by circles in Fig. '1 are each connected to one of a group of bars,

which are correspondingly numbered.

. The blocks C and bars 0 3' have beveled faces, and are arranged so as to provide" V-shaped grooves C between them, said grooves extendin longitudinally -of the cylinder C In the sides of the blocks C and bars C are formed shallow grooves C.

'The' insulation. between the blocks and bars preferably consists of strips 0 of vulcanized fiber and strips C of mica extending the full length of the bars and entering the grooves C, said strips serving to hold the blocks in place. The bars C are secured together by means of insulated end disks or plates C having annular ribs C thereon,

which extend into'grooves C in the bars. The blocks C (or fractions of bars) are placed end toend, provided with suitable 'insulation therebetween, so as to insulate one block from the next, and the terminal blocks are secured by the end plates in the same manner as are the bars. The end plates C are secured together by-means of the bolts C passing therethrough, or by any other suitable means. v The bars C may be electrically connected to'approximate blocks C in such a manner as to form the combinations exemplified in Figs. 11 to 17 inclusive, by means ofcertain contact pieces D Fig. 4, adapted to he slidingly moved through the respective grooves C by means of a longitudinally movable ring D which carries said contact pieces. The pieces D are slidably and radially mounted in the ring D. The contact pieces have wedge-shaped points corresponding in tions ofconnections disclosed in Figs. 11-

and 17inclusive, to the respective positions 1 to 7 inclusive of Figs. 8 and 9, consists ot a pair of feed screws E, rotatably mounted'in the motor framework. Each screw is provided with a nut E which is threaded on said screw, and the two nuts are connected by a semicircular rim" E extending half Way around the conta t ring D and at one side of the latter. Said nuts also have fingers E thereon, adapted to lie at the opposite side of said contact ring. A crank E upon the outer end ofone of the feed screws E provides means for rotating the latter. Motion is transmitted to': the other screw by means of gear pinions E E and the idler gear wheel E. \Vith the terminal bars andblocks of Figs. 6 and 9 connected to the coil terminals of F igr llin the manner indicated by the similarity of the reference characters, seven different speeds may be secured by moving the contact ring D into the seven difi'erent positions indicated in Figs. 8 and 9; and the movemeut of the ring D- from one position to another, to effect a change of speed of the motor armature may be accomplished while the said armature isin motion, as will be readily apparent.

' When the contact ring D is in position 1 (Figs. 8 and 9) the terminals of the armature coils (Fig. 1) will be connected by means of the contact pieces 1) making proper-electrical connection between the respective bars (1 and. blocks C", as indicated in Fig. 11'. This arrangement leaves three unused, or dead coils, having-terminals 50", 51"and 52" out of the circuit, and forms two series sets of 24 active coils, in each circuit, the coils of each set being in series with one another, and the two sets of coils being'inparallel with one another, or the two circuitsimplex'winding.

By shifting the contact ring D. to, position"2, the terminals will be connected together as shown in Fig. 12,. providing two circuits through the armature, each circuit comprising practically eighteen coils in series, With a shunt of six coils in parallel -with six .other coils in each circuit.

By shifting the contact ring D to position 3fit connects the terminals together, as indicated in Fig. 13, and provides four circuits through the armature, each circuit comprising practically twelve coils in series. The number of coils in series having thus been reduced from 24: to 12, the speed is approximately doubled. v w

lVhen the contact ring is shifted to position 4, four circuits, corresponding with Fig. 14, are'fo'rnied, there being practically ten coils in series in each circuit.

When thecontact ring D is shifted to position 5, corresponding With Fig. 15, six circuits are provided through the armature,

' and the number of coils in series in each c ircuit is reduced to. practically eight. In this case the speed Will be increased to three times the velocity obtained with the circuit arrangement indicated in Figs. 1 and 11.

lVith the ring in position 6, six circuits are formed, as shown ,in Fig. 16, each circuit having practically seven coils in series.

When the contact ring is placed in position 7 (Fig. 8) the terminals will be connected together as shown in Fig. 17 to form eight circuit-s throughthe armature, there being practically six coils in series in each circuit, and the speed will be practically four times as great as that obtained with the connections of Fig. 11, or the first described simplex connection.

The Words normally-open are used in the claims in a sense to express the conditions of the armature coils Without reference to the circuit-changer; as When the Winding of the armature is just completed, and before the application ofthe circuit changer, some of the coils are left open, to the terminals of which the various parts of the circuit-changer are to .be electrically connected. I

It will be noted that the circuit-changer is located, in an electrical sense, between the brushes, and that the brushes are not more in number than the poles.

It is evident that many modifications and variations may be madefrom the exemplification herein disclosed Without departure from the spirit and scope of my invention. For instance, a greater or less number, of the total number, of the coils of the armature may be actively included in the various schematic connections, than shown. and in some instances all of the coils in the armature may be included in the active circuit. I do not desire, therefore, to be limited to the precise structure and arrangement herein set forth except .fls indicated in the appended claims.

I claim as myinvention:

.1. A dynamo-electric Imachine' provided Withfll'tlllM-ttllp having-a plurality er ductive coils, a commutator having as many sections as coils to which said coils are connected in consecutive seras order, a' clrcuit changer adapted and arranged to vary the series and parallel relation of said coils in circuit, and a pair of brushes fixed with relation to each other and bearing onqsaid commutator.

2. A dynamo electric machine having an armature provided With a plurality of in Til number of'said coils in parallel and series relation.

3. A dynamo electric machine having an armature provided with a plurality of in ductive coils, in combination with an element of a circ'uitchanger consisting of a number of longitudinally arranged, insulated parallel bars connected to the terminals. of certain of said coils, and insulated blocks arranged fbr convenient electrical connection with certain of said bars respectively, also connected to certain of said coils, and an element of said circuit changer carrying contact devices arranged and adapted to electrically connect certain of said bars and blocks together to efl'ect different parallel and series relations of said coils, when moved to definite positions relative to the first mentioned element.

4. A dynamo electric machine having an armature provided With a plurality of in- I ductive coils, normally open, in combination With a circuit changer comprising a cylinder composed of a series of bars and a series of shorter blocks placed end to end, and alternating With said bars, said bars and blocks connected respectively to the terminals of certain of said coils, said cylinder secured to the shaft of said armature, and a device carrying a series of contacts for elec trically connecting certain of said bars and said blocks together, to electrically join the coils in different relations when said device is moved to certain selected positions to effect the given changes.

A-dynamo-electric machine having an armature prov'r with a plurality of normally open in duc ive coils, a commutator to wh ch said coils are permanently connected, and a circuit changer on the armature shaft for changing the series and parallel relation of said'armature coils.

. "6. A dynamo electric ina'chin'e having-an armature provided with a plurality of her mally open inductive coils, a commutator at one end of the armature to which said coils are permanently connected, acircuit changer located at the. opposite end of the armature and comprising parts connected respectively to said open coils, and having a laterally shiftable contact structure to etiect various electrical series and parallel connections between said (3011s, and having a laterally shiftable contact structure to ellect'various electrical series and parallel connections between said coils, and a means for laterally moving said shiftable coritactstructure to various: selected positions while the armature is in motion.

7. A dynamo-electric machine of variable active capacity having a drum armature provided with a plurality of'norIn-ally-open inductive coils, the core of the armature having coil slots therein, the slot pitch of the two sides of each armature coil being as great as possible without exceeding that determined by the total number of slots in the armature core divided by the number of field poles, and'means for adjustably grouping entire coils in circuits.

- 8. A dynamo-electric machine having an armature provided with a plurality of i normally open inductive coilsyand: means for changing the'electrical relation of said coils, the number of coils in said armature being equal to (R-l-2nR) i where R is the speed ratio, thenumber of equal to Where R is the speed ratio,'P the number of field poles and n some whole number.

10. A dynamo-electric machine comprising an armature, said armature being provided with windings of normally open coils, an armature shaft, a circuit-changer mounted onsaid shaft, the terminals of some of the portions of the armature winding being connected to said circuit-changer, and said circuit-changer having shifting contact means, certain portions or the armature winding being connected in series, and other portions of the winding being connected in series and as shunts in parallel with certain portions of the first mentioned series, said shunts being of greater inductive length when said contact means are in one position than when said means are in another position'. 1 I

ture having more than two circuits When said piece is in another position.

1.2. A dynamo-electr c machine hav ng a wave-wound armature provided with. a plurality of normally open coils', a circuitchanger mounted onv the armature shaft, one terminal only of substantially one-half of the coils of said armature being connected to said changer, and wires connecting eac of said terminals with one of the commutator segments of said armature, said circuit-changer comprising means for varying the electrical connections among said terminals and said segments.

. 13. A dynamo-electric-machine compris-- ing armature coils, and an armature shaft, coil-grouping means mounted on said shaft, 7 said means normally maintaining the armature coils in closed condition; said means comprising a movable member; said coils being grouped into a plurality of circuits,

with a plurality of coils in series in'each circuit when said member is in one position,

and when said member is moved to another; position said coilsbeing grouped into a plu- 'rality of circuits with fewer coils in series ineach circuit than when said member was in said first position. Y I

.14. A dynamo-electric --machine comprising an armature, a plurality of coils on said armature, an armature shaft, coil-grouping means mounted on said shaft, said means comprising a movable member, said coils being grouped into a plurality of circuits with more coils in series in each circuit but with fewer circuits when said movable member is in one position than when said member is in another position.

15. A dynamoelectric machine having'an armature provided with a plurality of :coils, a commutator on one end of the armature to which'the terminals of said coils are at all times connected when in operation, and a circuit-changer located on the opposite end of the armature and having a movable member'ada pted to vary the series and parsaid armature coils ha ving certain parallel and series connections when said pieceis in one position, and-When said piece is in another position said coils having different parallel and series connections.

17 A dynamo-electric machine having an armature provided with a plurality of coils;

a circuit-changer carried by the armaturev shaft, said changer comprising a SBI'IGS} of bars and blocks running parallel with said shaft, the terminals of some of said coils being electrically; connected to said bars and blocks; said-changer also comprising a longitudinally slidable member carrying con tacts, and means for sliding said member to various positions with reference to said bars and blocks to efiect various series and parallel connections of said coils. I

18; A dynamo-electric machine having a wave wound armature providedwith a plurality of coils, a circuit-changer carried .by

of the case in the Patent Oflice.

[SE-AL] Signed and sealed this 21st day of March, A. D., 1916.

the armature shaft, said changer compris- .ing a series of bars and blocks to which one ERNEST J. ANDREWS.

YVitnessesz V. L. SHEARMAN, Gnonen L. CHINDAHL.

It is hereby certified that in Letters Patent No. 1,123,161, granted December 29, 1914, upon the application of Ernest J. Andrews, of Chicago, Illinois, for animprovement in Dynamo-Electric Machines, errors appear in the printed specification requiring correction as follows: Page 3, line 106, strike out the article the"; same page, line 125, after the word all insert the word of; page 5, line 43, for the word slow read slot} page 8, lines 9-12, claim 6, strike out the words and having a laterally shiftable contactstructure to effect various electrical series and parallel connections between said coils and that the said Letters Patent should be read with these corrections therein that the same may conform to the record J. T. NEWTON, Acting Commissioner of Patents. 

